Interaction between beta-thalassaemia and Hb G Philadelphia associated with alpha-thalassaemia.

A man who did not produce and beta-chains did not suffer from a severe beta-thalassaemia. He was heterozygous for Hb G Philadelphia. It has been suggested that this haemoglobin variant was associated with alpha-thalassaemia and that interaction between alpha-thalassaemia and beta-thalassaemia decreased the imbalance of alpha/beta-globin biosynthesis and thereby the severity of the beta-thalassaemic disorder.

Is haemoglobin G alpha Philadelphia linked to alpha-thalassaemia?

The question, "Is Hb G alpha Philadelphia linked to alpha-thalassaemia?" was first posed because the abnormal haemoglobin is found in heterozygotes at a concentration greater than 25%, the proportion predicted from a 4 alpha-chain gene model. Globin chain biosynthesis was studied in a West Indian family in which one parent had beta + thalassaemia and the other was heterozygous for the G alpha Philadelphia chain gene. The former had a globin chain production ratio alpha/beta well above 1, while the latter had a ratio significantly less than 1.